Ash Tree Insects and Diseases

If you have ash trees on your property, it’s important to be aware of conditions that affect the health of your trees, including ash tree insects and diseases. Knowing what conditions can impact your trees can raise your awareness and help prevent future problems.

Ash Tree Insects

A number of insects feed off of ash trees and can easily get out of hand. Some of the biggest pests include:

– Blackheaded ash sawfly

– Ash sphinx

– Woolly ash aphid

– Ash borer

– European fruit lecanium

– Banded ash clearwing

– Ash cambium miner

– White-banded ash bark beetle

– Ash seed weevils

– Ash flowergall mite

Unfortunately, this is nowhere near a complete list. Some of these insects destroy the leaves of ash trees while others bore into the bark and kill the tree from the inside. Leaves that appear ragged and holes in the bark of your trees are usually the first indicators of an infestation. Insecticides can usually be used to bring infestations under control, although it might be necessary to call in a professional to assist with proper application.

Ash Tree Diseases

Ash trees are also prone to a number of diseases. A single diseased ash tree can quickly infect an entire grove. Some of the identified ash tree diseases include:

– Anthracnose

– Powdery mildews

– Ash rust

– Mycosphaerella leaf spots

While some of these diseases are more prevalent in other parts of the country than others — for example, ash rust most commonly affects trees east of the Rocky Mountains — ease of travel has allowed the diseases to spread beyond their normal range. Diseases due to fungal infections can be treated with fungicide to control the spread of the fungus. Badly infected trees may have to be destroyed in order to protect healthy trees. For some diseases, including Mycosphaerella leaf spots, no effective method of control has yet been found.